1. Field of the Invention
The present invention relates to a transfer vessel for transferring a specimen between two vacuum apparatuses while maintaining the specimen under a high vacuum. The invention is also concerned with a method of transfer using the device.
2. Description of the Related Art
In general, when a specimen which has been subjected to various kinds of treatment in a vacuum apparatus having a high or medium degree of vacuum is temporarily removed from that apparatus and is then accommodated again in that vacuum apparatus or in another vacuum apparatus, it is often necessary to transport the specimen without exposing it to the atmosphere, while maintaining it under vacuum. Hitherto, a transfer device, such as the one shown in FIG. 2, has been used to meet this requirement. This transfer device has a container body 1, a coupling portion 2 provided at a lower portion of the container body 1 adapted to be selectively opened or closed, and a vacuum pump 4 constituted by an ion pump or the like hermetically connected to a side portion of the container body 1 via a connecting portion 3. In operation, the coupling portion 2 is hermetically coupled to a vacuum apparatus (not shown) with the coupling portion 2 closed. At the same time, the inside of the container body 1 is evacuated so as to maintain it at a high or medium degree of vacuum. In this state, the coupling portion 2 is opened and a specimen 5 is transferred from the vacuum apparatus to the inside of the container body 1. After the specimen 5 has been supported by a holder 6 which is installed on an inner wall of the container body 1, the coupling portion 2 is closed. Subsequently, the coupling portion 2 is either opened and the specimen 5 is accommodated again in the vacuum apparatus or the coupling portion 2 is separated from the vacuum apparatus and coupled with another vacuum apparatus so that the specimen 5 can be accommodated therein.
Thus, the specimen 5 can be transferred between vacuum apparatuses without being exposed to the atmosphere.
However, in order to maintain the degree of vacuum inside the container body 1, it is necessary to constantly operate the vacuum pump 4 during transportation by supplying electric power to the vacuum pump 4 from a power source (not shown) via a power cable 7. Since the power source is normally fixed, this method has a drawback in that the range of movement of the transfer body is restricted within the movable range of the power cable 7.
In addition, there is another drawback in that the transfer device is expensive since a vacuum pump is used.